1. Field of the Invention
The present invention relates to a display panel applied to flat panel display devices, and particularly, to a plastic display panel and a flat panel display device having the plastic display panel.
2. Discussion of the Related Art
Flat panel display (FPD) devices are applied to various electronic products such as portable phones, tablet personal computers (PCs), notebook computers, etc.
The FPD devices include liquid crystal display (LCD) devices, plasma display panels (PDPs), organic light emitting diode (OLED) display devices, etc. Recently, electrophoretic display (EPD) devices are widely used as the FPD devices.
FIG. 1 is a view schematically illustrating a configuration of a general FPD device having a non-plastic display panel. FIG. 2 is a sectional view of an example illustrating a state in which the display panel of FIG. 1 is adhered to a driving integrated circuit (IC) by a conductive member according to a related art.
The FPD device, as illustrated in FIG. 1, includes a display panel 10 that displays an image, a printed circuit board (PCB, main board) 70 on which various circuit components are mounted, a flexible printed circuit (FPC) 60 that electrically connects the PCB 70 to the display panel 10, and a driving IC (D-IC) 20 that is mounted on a lower substrate 15 of the display panel 10 and drives the display panel 10 according to electrical signals transferred from the PCB 70 through the FPC 60.
The display panel 10 may be of various types of panels, such as a liquid crystal panel, a PDP, an organic light emitting display panel, an EPD panel, etc., depending on the types of the above-described FPD devices. Generally, the display panel 10 is configured with an upper substrate 16 and the lower substrate 15.
The display panel 10 includes a display area that displays an image, and a non-display area that does not and cannot display an image. A plurality of output link lines 30 electrically linking the driving IC 20 to a plurality of panel lines (e.g., gate lines and/or data lines) disposed in the display area of the display panel 10, and a plurality of input link lines 50 electrically linking the driving IC 20 to the FPC 60, are arranged in the non-display area of the display panel 10. The lower substrate 15 of the display panel 10 includes a non-plastic base substrate 11 on which the link lines 30, 50 are formed, and an insulating layer 12 and a passivation layer 13 covering the link lines 30, 50 over the base substrate 11.
The driving IC 20 may be a data driver IC for driving the data lines of the display panel 10, a gate driver IC for driving the gate lines of the display panel 10, or a display driver IC (DDI) for integratedly driving the data lines and the gate lines. In FIG. 1, the driving IC 20 is a display driver IC.
In a chip-on glass (COG) type in which the driving IC 20 is directly mounted on the display panel 10, as illustrated in FIG. 1, when an anisotropic conductive member 40, such as an anisotropic conductive film (ACF), is disposed between the plurality of link lines 30 and 50 and the driving IC 20 and is pressed against the lower substrate 15 of the display panel 10 by the pressing of the driving IC 20, the driving IC 20 is electrically connected to the link lines 30 and 50.
To this end, as illustrated in FIG. 2, a link terminal (bump) 21 is disposed at one side surface of the driving IC 20 corresponding to the link lines 30 and 50, and thus, when the driving IC 20 is pressed downwardly, a lower side surface of the link terminal 21 presses on a conductive ball 42 included in the conductive member 40 and is hardened, thereby electrically linking the link lines 30 and 50 to the driving IC 20. In this case, a plurality of transparent electrodes 31 and 51 are formed on the link lines 30 and 50, for assisting the electrical connections between the link terminal 21 and the link lines 30 and 50.
In this case, a sufficient number of conductive balls 42 are compressed or pressed by the link terminal 21 to ensure electrical connection between the display panel 10 (e.g., link lines 30, 50) and the driving IC 20. Therefore, the above-described compression/pressing process necessarily needs an operation that tests whether the conductive balls 42 are sufficiently pressed by the link terminal 21, which indicates a proper and sufficient electrical connection between the link lines 30, 50 and the driving IC 20.
To this end, a scheme may be used in which a microscope is disposed under the non-plastic display panel 10 so as to check fine indentations 32 and 52 formed on the transparent electrodes 31 and 51 or the link lines 30 and 50 through the display panel 10, and a camera captures images of the indentations 32 and 52 checked by the microscope to acquire image data. Here, the indentations 32, 52 denote squashed marks that, when the conductive ball 42 is compressed between the link terminal 21 and the lower substrate 15 of the display panel 10, are formed on the transparent electrodes 31 and 51 or the link lines 30 and 50 due to the dent made by the conductive ball 42. That is, if there is a sufficient number of indentations 32, 52 made by the conductive ball 42, then that denotes that the link lines 30 and 50 are closely adhered to the link terminal 21, and denotes that the link terminals 21 are electrically connected to the link lines 30 and 50.
In contrast to the non-plastic panel of FIG. 1, recently, the use of FPD devices using a plastic panel, which is not damaged even when being folded or rolled, is increasing.
Especially, e-books which users can carry and use are manufactured with an EPD panel, in consideration of characteristics in which power consumption is low, the cost is low, and the e-book is accommodated and kept in a space with various articles placed therein like bags. The EPD panel is manufactured as a plastic display panel.
In addition to the e-books, various electronic products are manufactured with the plastic display panel for a portability reason. In addition to the EPD panels, liquid crystal panels, plasma display panels, organic light emitting display panels, etc. may be manufactured as the plastic display panels.
Here, the plastic panel denotes a display panel in which a base substrate configuring the display panel is formed of a synthetic resin such as plastic. When manufacturing the plastic display panels, however, a test is needed to verify that the driving ICs are in electrical contact with the link lines of the lower substrate of the plastic display panel.